's Forth
Bungard's Forth 0.8 is an open source implementation of the Forth programming language. It is a 16-bit, native-code Forth system for IBM PC-compatible computers. This Forth system includes an editor, assembler, kernel, graphics and windowing system, debugger, and file utilities. It runs on DOS and Windows 3.1 and DOS with XMS or extended memory. The system was written in assembly and has been optimized for speed and size. The editor supports both line-by-line and direct interpretative entry of Forth code. The system features fast subroutine calls, abbreviations, auto-start, and other convenient features that make it easier to program the IBM PC family of computers in Forth.